Typically, the apparatuses include booms made of carbon fiber composite material. For example, such apparatuses are used in space technology, for example to span solar sails. It is desired that these apparatuses have a low mass or weight, respectively, and that they may be transported in a space-saving manner taking their comparatively great length of the unwound booms in space into account. Additionally, unrolling the booms has to be reliable, and the booms need to have maximum stiffness and to be located in a defined position with respect to the remainder of the apparatus in their unwound position.
An apparatus is known from “Solar Sail Technology Development And Demonstration” M. Leipold et al., Annual 2000, Deutsche Gesellschaft für Luft-und Raumfahrt (DGLR), Leipzig, Germany, September 2000. The known apparatus includes four booms having compressed cross sections and being rolled up on a common drum. The drum is arranged to be rotatable with respect to the remainder of the apparatus. The feet or basis of the booms are located on the drum in a radial inward direction of the drum close to its circumference, and the tips are located on the drum in a radial outward direction of the drum, meaning relatively far away from the outer circumference of the drum. The tips of the booms already have their expanded cross section even before unfolding the booms. The expanded cross section is stabilized by insert portions being located in the interior of the booms. To unwind the booms, guiding tapes are wound up from the drum, the guiding tapes being located between the separate booms. The booms are guided between the guiding tapes until they have reached their expanded cross section, meaning until they have sufficient stiffness. After having completely unwound the booms from the drum, the drum has to be fixed to allow for expansion of the cross section of the booms at their feet being connected to the drum. The entire mass of the known apparatus is comparatively great taking into account the mass of the drum on which the booms are wound up, the mass of the drives for pulling off the guiding tapes from the roll of booms, and the mass of the guiding tapes. Furthermore, it has to be taken into account that the technical expenditure for fixing the drum after having unfolded the booms and for expanding the cross section of the feet of the booms being connected to the drum is substantial.